Method for the manufacture of propionic aldehyde



Iatented Mar. 14, 1939 Mn'rnon ron THE MANUFACTURE or rnoProNIc ALnEnrnn Milton Gallagher and Rudolph Leonard Hasche,

Kingsport, Tenn., assignors, by mesne assign- -ments, to Eastman Kodak Company, Jersey City, N. J., a corporation of New Jersey I Application July 3, 1936, Serial N0. 88,822

9 Claims.

This vinvention relates to the manufacture of saturated aliphatic aldehydes and acids and, more taining an even number of carbon atoms and particularly, to a process for the manufacture of propionic aldehyde and propionic acid.

Propionic aldehyde, also referred to as propanal, with which this invention is particularly concerned, has the formula: CHaCHzCHO. Saturated aliphatic aldehydes and acids and, in particular, propionic aldehyde and acid have a number of uses. These organic compounds may be converted to other chemical products. Forexample, propionic acid'is employed in the manu.- facture'of cellulose esters. Propionicl aldehyde may serve as a material for the production of propionic acid and employ the oxidation procedure described in Hasche copending application No. 34,215 of August 1, 1935.'

While some saturated aliphatic aldehydes contheir methods of preparation are known', apparently few methods have been. developed for the manufacture of the saturated aldehydes and acids containing an odd number of carbon atoms, y

such as propionic aldehyde and acid with which the present invention is particularly concerned.

Prior to our invention the manufacture of propionic aldehyde has been connned in a number of instances to the dehydrogenation of alcohol or processes involving pressure synthesis.

We have found a new method for the manufacture of saturated 'aliphatic aldehydes and, in

particular, for the manufacture of aldehydes containing an odd nurnbei` of carbon atoms in the molecule,l which is superiorin a number of respects to processes previously employed in the manufacture of saturated aliphatic aldehydes.

This invention has for an object to provide a process for combining two diiferent'aldehydes in thevapor phase to form an aldehyde which may contain either an odd or an even number of carbon atoms. Another object is to provide a process for the production of saturated aliphatic aldehydes containing an odd number of carbon atoms in the molecule. Still another object is to provvide avaporand liquid phase catalytic process farine-production of saturated aliphatic aidehydes. iriiitliiir object is to provide a simple and eillcient process for the production of saturated aliphaticaldehydes which operate o'n readily produced or available raw materials. Still another `object is to provide. a catalytic process for the reaction of a plurality of aliphatic aldehydes con taining a die'rent number of carbon atoms in 4' the molecule and the subsequent conversion of the reaction products to saturated aldehydes. -A still (Cl. 2GB-601) object is to provide a catalytic process for the I production of acrolein and the conversion of this product to propionic aldehyde. As another object we provide for the formation of a threecarbon atom from formaldehyde and acetalde- .hyde which may later be converted into propionic acid'by'oxidation. Another object is to provide a process wherein unreacted products may be re-utilized as starting materials. A further object is to provide a process which operates without pressure, but may include the use of pressure if desired.

Still another object is to provide catalysts and catalyst supports for a process involving the reaction of aldehydes containing a .different number of carbon atoms in the molecule to obtain saturated aldehydes. Another object is to provide catalysts and catalyst supports for the reaction of materialacontaining formaldehyde with materials containing acetaldehyde to obtain saturated aldehydes, by reduction of the resultant reaction products. N

. Still another object is to provide apparatus which is simple andinexpensive yet suitable for the'reaction of various aliphatic aldehydes to obtain unsaturated aliphatic aldehydes therefrom coupled with the conversion thereof to saturated aldehydes and acids.

Other objects will appear hereinafter.

These objects are accomplished by the following invention which includes the steps of catalytically reacting at least two aliphatic aldehydes having a different number ofcarbon atoms in the molecule followed by reduction of the reaction mixture. In accordance With our preferred procedure, we have found that excellent yields of propionic aldehyde may be obtained by catalytically reacting formaldehyde and acetaldehyde followed by reduction of the reaction products.

For further details concerning our new process and apparatus and a more complete understanding of our invention, reference' is made to thepresent application. Inthe accompanying draw- Fig. 1 is a diagrammatic side elevation showing `an apparatus set up Afor practicing our. new

. accompanying drawing which forms a part of the ing, in which like reference characters refer t0 like parts,

'tank is connected 'by conduit l2 to the mixing point i5. Another feeding device i6 is provided for another component. Conduit il connects this device with the mimng point.

i3 leads from the point to the vaporizer il. "Or, in place of the two tanks, il and IE, the

two dierent aldehydes may be premixed in the desired proportions in a single tank and fed to the vaporizing or dashing device.

.The apparatus il may be of well-known construction and include heating elements, spraying means or other elements for converting liquids to vapors. Vaporizer il is connected by conduit i8 to catalyst unit i9.

Catalyst unit i9 maybe maintained at the properA temperature by means of a coil 2|. The outside of the unit is insulated as at 22. Also, if desired, the conduits i8. and 24 may be heated. The catalyst unit includes a charge of catalyst 23. Conduit 24 is provided for withdrawing the reaction products to a catalyzer or other treatment. The catalyst units are equipped with thermometer wells 25 and 35 whereby the temperature in the interior of the units may be measured by insertion of a thermocouple or thermometer.

Conduits 24 and 2l connect catalyst unit IS with a second unit 28 of similar construction.' Unit 28 comprises heating elements 29, reaction chamber 3i. In place of this unit any wellknown hydrogenation unit may be employed.

A conduit 32, joining conduit 2id-2l, or leading directly into unit V2li is provided for the introduction of a hydrogenating medium. Conduit 33 which leads through condenser 36 is provided for withdrawing the reaction products. It is understood that the various feed tanks, feed lines and the like' will be equipped with vent ccndensers, pop valves and the like.

In Fig. 2, 52 represents a feed tank for one o f the starting materials. The tank is connected by conduit 53 through a meter 5d or other suitable device tovaporizer 56. Vaporizer 56 is connected by conduit 51 to mixing valve or chamber 58.

In a similar manner another feed tank 62 is provided for the other starting material. Tank $2 is connected by conduit 6i through a rotameter 65 to a vaporizer or boiler 63. Conduit B4 connects boiler 63 with mixing chamber 58. The feed tanks, feed heaters, boiler or vaporizers in the system will include jackets or other temperature controlling means as at 66, 61 or Eil for the purpose of regulating the temperature ofv the respective containers. In the apparatusshown in Fig. 2 this would be done by injection of heating or cooling fluids in the jackets as the situation required. v

The mixing valve or mixing chamber 58 may be connected by conduit t8 through heat. ex-

changer il to a catalyst chamber 12. This heat The catalyst chamber comprises a catalyst conexchanger is provided with a valved by-pass 92.

tainer filled with catalyst. This catalystmay be retained by screens or other means as at 13 .and 14. The catalyst is enclosed in temperature controlling jackets 10, 16. The jacket 16 may be heated by steam, hot oil, molten chemicals, electric heat or in some otherl suitable manner, or cooling uid may be injected if necessary. 4'Iihe 'I'he conduit y aisance chamber 10 is provided so that the incoming mixture may be passed in heat exchange relationship with the catalyst to absorb heat or reaction therefrom.

While we have described the above type catalyst chamber other types of catalyzers may be employed, such as for example the various other catalyzer units shown in Hasche copending application No. 34,215. Also in the present set-up it is possible to use the vaporizers andother type equipment shown in Hasche application No. 34,215.

Catalyzer il is joined to condenser 'l1 by conduit l5. This condenser may be oi. the usual construction. A valved conduit li'. is provided in order that the condensate vmay be Withdrawn from the condenser to tank 19. Means for the separation of unreacted aldehydes and return to feed may be inserted in system, as'in line 18 for example.

Tank 'i9 is arranged so that its contents may be caused to ow through conduit 8i by pumping or gravity feed, to a reduction unit 82. 'I'he reduction unit may comprise any standard hydrogenation unit.

Leading into the catalyst chamber, or into conduit 8l is a valved conduit 8l through which the reducing medium, such as hydrogen or material yielding nacent hydrogen may be introduced.

The catalyzer (or hydrogenation chamber) is provided with conduit 88 which leads to condenser 89. Condenser 89 is equipped with a valved draw-oif conduit 9i. y

Catalyst chambers 23 and 'l2 are iilled with catalyst. A number of catalysts have been y found to be satisfactory for thereaction of an aliphatic aidehyde with a dierent aliphatic aldehyde. Silica or alumina gel alone appear to be satisfactory catalysts. 'Howeven the action of these gels may be improved by impregnating them or incorporating therewith additional materials, such as sodium acetate, magnesium acetate, cadimium acetate, thoria, molybdenum oxide or cobalt metal. When we refer to gel catalyst we refer to catalysts such as described above. While the above catalysts are satisfactory, our invention is not limited to these catalysts or catalyst supports. For example, a suitable catalyst for carrying out our aldehyde reaction is magnesia supporting about 2-10% of metallic cobalt. Or magnesia formate, vanadium pent oxide or tungstic oxide, on a gel carrier may be employed. Or magnesium oxide made into granular form is satisfactory. The temperature conditions under which any particular catalyst will operate in our process mayl vary somewhat. Temperatures between about 200400 C. appear to be satisfactory, and within this range the range of about 290 C. to 300 C. appears preferable in many instances.

The operation of our new process and apparatus may be better understood by reference to the following examples which are set forth merely for the purpose of illustration. The following example is described as carried out in the apparatus of Fig. 1.

The container Il was filled with a relatively pure liquid acetaldehyde. Container i5 was filled with formalin. A metered amount of acetaldehyde was mixed with formalin at I5. This mixture was conducted through conduit I3 into flash apparatus I1. j-

The mixture of acetaldehydeA and formaldehyde were readily vaporized in Il and the mixture of vapors conducted through conduit i8 to catalyst unit 18. The catalyst unit had been heated'and during the reaction was maintained in a heated condition by means of an electrical heating coil 2|.

During the run of this examplev approximately 101.3 grams of acetaldehyde and approximately 84, grams of formalin containingapproximately 35% formaldehyde by weight were fed to the catalyst unit. Thel catalyst chamber, which was filled with one of the aforementioned catalysts,

was held at about 285 C. by electrical heating.

`genation catalyst such as copper, nickel, platicontained approximately 85.0% H2.

num, etc. However, in the hydrogenation step it is desirable to avoid the use of a catalyst which is too active and which would carry reduction t'oo far thereby resulting in the production of excessive quantities of propyl alcohol. One satisfactory catalyst is nickel resulting from an alloy of nickel with aluminum, silicon or the like'. These other components are removed from thef nickel before its use as a catalyst. In this par-l ticular run the temperature was held at about C.

` The reaction products were conducted from unit 28 through conduit 33 and condenser 36 and into a fractionating column (not shown). The

condensed product on fractionation consisted approxmately of 47.1 grams-of acetic aldehyde. 51.8 grams of propionlc aldehyde, 13.3 grams of ethyl alcohol, certain amountsl of unreacted formic aldehyde, and methanol. The exit gases This yield of the saturated aldehyde, propionic aldehyde, indicates that a satisfactory yield of the unsaturated aldehyde, acrolein was obtained in the preceding step.

The following example is described with respect to Fig. 2. Tank 52 .was filled with commercial, acetaldehyde. Inasmuch as acetaldehyde has a boiling point of 'about 21 C. it may be desirable to circulate a cooling medium in jacket 66 to prevent volatilization of the aldehyde. In place of the cooling jacket it is, of course, apparent ythat cooling coils may be immersed in the acetaldehyde. Theacetaldehyde was fed through rotameter 54 into vaporizer 58.v Acetaldehyde va- `gorssafrom 56 were conducted to mixing cham- In our process it is possible to use acetaldehyde from various sources. For example, the acetaldehyde may be obtained synthetically from acetylene. The acetylene may be produced from calcium carbide, cracking hydrocarbons or the decomposition of hydrocarbons in an electric arc. The acetaldehyde may valso be obtained from ethyl alcohol. The use 1of aldehyde from this source will be'described in more detail hereinafter.`

Formaldehyde (or materials containing formaldehyde) was placed in container 82. This container may be heated or cooled or otherwise acted 'upon dependent upon 'the particular formaldehyde material.

Relatively pure formaldehyde boils at approximately -21 C. Formalin, which contains around 40% of formaldehyde, the remainder being principally methyl alcohol and water has a higher boiling point and is an easier source. of`

formaldehyde to work with. Also formalin is readily available commercially. We have found that the methyl alcohol content of formalin or of other sources of formaldehyde does not interfere with our process. Solid paraformaldehyde may be employed. It is, therefore, apparent that our invention embraces various sources of formaldehyde. We also contemplate the added steps of converting methyl alcohol into formaldehyde and feeding the resultant reaction mixture through conduits 6I and 84.

In the example under description the forinaldehyde materials were fed through rotameter 65 into the formaldehyde boiler 63. The evolved vapors containing formaldehyde were conducted through conduit 84 to the mixing point 58. From 58 the vapors containing formaldehyde and acetaldehyde, with or without water, methyl alcohol and other non-detrimentalcomponents, were passed into and through catalyst 12. This catalyst which comprised either silica or alumina gel, was heated t`o approximately 290 C. to 300 C. After a period of operation, which may be from 12 to 24 hours, the catalyst may be regenerated.

The following reaction apparently took place:

vThe vapors from the catalyst chamber comingA off at 15 were passed through cooling device 11. At 18 acrolein containing some water, unreacted formaldehyde and acetaldehyde was withdrawn to tank 19.

The reaction of two different aliphaticaldehydes, such as formaldehyde with acetaldehyde, per se, is described and claimed in our co-pending application Serial No. 88,821 entitled Process for the manufacture of unsaturated aldehydes and apparatus therefor.

The condensed materials of acrolein, formalin, acetaldehyde and water may be Vaporized and conducted from tank 19 into hydrogenation unit 82. Or, the materials in the uncondensed condition, as at 15, may be passed `:iirectly to the hydrogenator in a manner similar To that of Fig-1. As indicated above, any well-known hydrogenation catalyst such as nickel, copper and the like, either in the form of 'a supported catalyst,

or in solution, or in a vaporous state may be terlals were charged into the hydrogenation apparatus. A temperature of between 50-400 C. was maintained in the hydrogenator.

Our hydrogenation proceeds selectively to reduce the double bond of the acrolein yielding propionaldehyde. Apparently the hydrogen does not attack the aldehyde group. .The acetaldehyde and formaldehyde present with the acrolein are not appreciably attacked during the reaction. This is observed by measurement of the absorpa arcaicav Propionic aldehyde O Hydrogen The liquid in the hydrogenator at the end of the reaction was subjected to fractional distillation. The acetaldehyde, boiling at approximately 20 C., was rst distilled oi. The next fraction boiling at about 47 C..contains propionic aldehyde. This fraction containing the propionic aldehyde may be fed through any of the oxidation units shown and described in Hasche copending application Serial No. 34,125. By such treatment, the propionic aldehyde may be catalytically oxidized to propionic acid.

The above examples are merely illustrative of conditions for carrying out our process. Reaction conditions in the various steps may be altered land the above examples are not to be construed as limiting our invention.

For example, the mol ratio of acetaldehyde to formaldehyde while generally kept within the range of from -.5, may be varied outside of these limits. Generally we employ excess of the acetaldehyde and otherwise operate the process to consume the most, if not all of the formaldehyde in one pass. The reaction products collected in i9 would consequently show excess acetaldehyde but smaller formaldehyde. The subsequent hydrogenation step may convert some of the acetaldehyde into ethyl alcohol. 'Howeven the ethyl alcohol may be separated or converted to acetaldehyde by any of a number of Vlrnovvn processes and the acetaldehyde returned to the first step of our process along with` unreacted acetaldehyde.

Any formaldehyde which becomes hydrogenated into methanol maybe reconverted and refed through the system.

The space velocities employedin the formation oi the unsaturated aldehyde which is subsequent- Vly hydrogenated may vary according to conditions and reaction equipment. We have found the range, from approximately 200 to 3000, to be sultable for carrying out the reaction ci two different aliphatic aldehydes. We may define space velocity as cubic feet of reactants fed per cubic foot catalyst per hour--volumes of reactant materials measured at temperatures and pressures of reaction. As already indicated the temperature range for' reacting formaldehyde with acetaldehyde may varyfrom about 200 C. to

1 400 C. While we prefer to carry out the formjaldehyde-acetaldehyde reaction under atmospheric conditions it is possible to carry out the reaction under either higher or lower pressures. -fWith respect to the hydrogenation step, this 'motion-may be carried out at temperatures in of 200-300 C. and in the vaporphase. Various. pressures varying from about substantially no pressure up to 300 or 400 pounds are satisfactory, although no pressure `or the lower f'fpressures within this range are preferred, be-

cause of'simpliclty of operation and construction '-"j ct equipment.

of aliphatic-aldehydes containing an odd number of carbon atoms such as propionic aldehyde. permits the utilization of materials, such as' formalin, acetaldehyde and hydrogen. Our process is also particularly desirable from the standpoint that any by-prcducts produced are few in number and in relatively small quantities, when our process is properly employed. The by-products may be re-used. Any unreacted components may be reutilized by circulation through the system.

It will be understood that our apparatus will be constructed of suitable materials and that proper precautions for preventing heat losses and leakage will be observed. We nd that many of the parts of our apparatus may be constructed of a steel containing about 16-23% chromium, about 4'Z%-20% nickel and the balance substantially iron. This steel preferably has a content of carbon of about .10% or less. The steel may also contain small amounts of copper, silicon, molybdenum and tungsten.

The term rotameter as employed'herein refers to liquid measuring devices.

It is, therefore, apparent that while we have described our invention in some detail there are many changes that may be made therein without departing from the spirit of the invention.

What We claim arid desire to secure by Letters Patent of the United States is:

l. A process for the production of a saturated aliphatic aldehyde. which comprises reacting two dierent aliphatic aldehydes, each having a lesser number of carbon atoms in the molecule than the aldehyde to be produced, in the presence of a catalyst, maintaining conditions at least part of the time whereby the reaction Will take place in the vapor phase to yield a reaction mixture containing an` unsaturated aldehyde. 'at least one saturated aldehyde and water, continuously subjecting this reaction mixture in the vapor phase to a treatment which causes hydrogenation of sutstantially only the unsaturated aldehyde to space velocity Within the range 'of from 200 to' 3000, in contact with a catalyst maintained at atemperature between about 200 C. and 400 C. to yield a reaction mixture containing an unsaturated aldehyde, at least one saturated aldehyde and Water, and subjectingat least a part oi this reaction mixture while in the vapor phase to a treatment which causes hydrogenation of substantially only the unsaturated. aldehyde, thereby producing the desired saturated aldehyde.

3. A process for producing saturated aliphatic aldehydes, which comprises passing materials containing at least two diierent aliphatichldehydes in the vapor phase at space velocities between 300 to 2000 into contact with a gel catalyst maintained at a temperature between about 200 C. and 400 C., condensing the reaction products to yield a reaction mixture containing an unsaturated aldehyde, at least one saturated aldehyde and water, substantially immediately subecting4 this reaction mixture in the vapor phase to a treatment at a temperature between C.- 400 C. in the presence of a hydrogenation catalyst and medium to cause hydrogenation of the unsaturated aldehyde to a saturated aldehyde, and separating this saturated aldehyde from the reaction mixture by distillation.

4. A process for the production of propionic aldehyde, which comprises reacting formalin with acetaldehyde in the presence of ,a gel catalyst containing a metal acetate, the reaction being maintained under conditions of temperature and pressure which cause the formation of reaction productscontaining acrolein, a saturated aldehyde and water, subjecting at least a part of this reaction mixture to catalytic hydrogenation at a temperature between 50 C.400 C. in the presence of hydrogenation medium 'so that the acrolein is hydrogenated to propionic aldehyde but the other omponentsof the reactionmixture are not substantially hydrogenated'l 5. Thechemical process which comprises reacting formaldehyde and acetaldehy'de in the vapor phase and in the presence of a gel catalyst maintained at a temperature between about 150 C. and 400 C. to produce reaction products containing acrolein, acetaldehyde, formaldehyde and water, condensing the reaction products produced, andvsubjecting at least" a partof'the re= action materials to catalytic hydrogenation under conditions sufficiently vigorous to cause the. hydrogenation of acrolein but insufficient to cause substantial hydrogenation of other materials in the reaction mixture.

v6. The chemical process for the production of a straight chain aliphatic aldehyde, which comprises preparing \a reaction mixture containing the corresponding unsaturated aldehyde by the reaction in the vapor phase of other aldehydes, andthen substantially immediately subjecting the reaction mixture in the vapor phase to a hydrogenation treatment wherein unsaturated aliphatic aldehyde is cog'erted to said straightchain aldehyde, and sepa ting the straight chain aldehyde from thereaction mixture.

'1.- .A process for the production of aliphatic aldehyde compounds, which comprises vaporizing an aliphatic aldehyde containing a lesser number of carbon atoms than the aldehyde being produced.

ying the reaction hydrogenation of other components of the reaction mixture, and separating the desired aldehyde from the reaction mixture.

8. The chemical process which comprises vaporizing an aliphatic aldehyde containing less than four carbon atoms, vaporizing another and different aliphatic aldehyde, reacting at least a part ofthe resulting aldehydevapors in the presence of a gel containing catalyst maintained under temperature and pressure conditions which will cause reaction between the vaporized aldehydes, cooling the reaction products, and subjecting the reaction products to treatment with.

free hydrogen, in the presence of a hydrogenation catalyst.

9. A process for the manufacture of propionic aldehyde, which comprises vaporizing materials containing. acetaldehyde, vaporizing materials containing formaldehyde, reacting together at least a part of the vaporized materialsin the presence of a catalyst maintained at a temperature between about 200 C. and 400 C., subjecttloned treatment to condensation and then to hydrogenation in the presenceof a nickel hydrogenation catalyst derived from an alloy of nickel.

- lmn'lON-GAILAGHER.

RUDOLPH LEONARD HABCHE.

products from the aforemen 

